fix unclear description and lack of usage in the editor.

closes #4059

removed added code in the seed

seed/challenges/object-oriented-and-functional-programming.json

@@ -189,7 +189,7 @@
       "title":"Iterate over Arrays with .map",
       "description":[
         "The <code>map</code> method is a convenient way to iterate through arrays. Here's an example usage:",
-        "<code>var timesFour = array.map(function(val){</code>",
+        "<code>var timesFour = oldArray.map(function(val){</code>",
         "<code>&thinsp;&thinsp;return val * 4;</code>",
         "<code>});</code>",
         "",